Optimization of atomization parameters in the speciation of organotin compounds by hydride generation–gas chromatography–electrothermal atomic absorption spectrometry

Abstract

The detection of organotin hydrides by electrothermal (quartz furnace) atomic absorption spectrometry coupled on-line with hydride generation is closely dependent on several parameters such as the geometry of the quartz cell and the flow rates of additive gases. The influence of the design of the atomizer and the effects of the gas flow rates were evaluated in this study. The design of the quartz cell atomizer is not critical provided that a few rules are followed: the helium flow carrying organotin hydrides should be mixed with hydrogen in as small as possible dead volume (no mixing chamber) and oxygen introduction should be made as close as possible to the light path. The ratios of gas flow rates must be optimized for each cell design, the most important being the H₂:O₂ ratio chosen to produce highly reducing working conditions. Detection limits obtained after optimization ranged from 30 to 130 pg depending on the conditions and species.